- 标题
- 摘要
- 关键词
- 实验方案
- 产品
-
First Principle Study of Optical Properties of Cu doped zincblende GaN for Novel Optoelectronic Applications
摘要： Current computational study is focused on calculation of optical properties of Cu doped zincblende GaN system where PBE-GGA approximation is employed in Wien2K code. We consider various Cu concentrations 6.25%, 3.12%, 1.56% corresponding to 1× 1 × 2, 1 × 2 × 2, 2 × 2 × 2 supercell configurations respectively. We substitute one Ga atom with one Cu atom in each concentration and we present a good comparison among optical properties of pure GaN and all Cu concentrations. TDOS and PDOS plots reveal contribution of Ga p-states, N p-states and Cu d-states. Optical absorption shows redshift in comparison to pure GaN and because of interactions of Cu and N atoms, we inspect localized d-states at minima of conduction band or Fermi level. Hence, electro-optical properties of zincblende GaN are enhanced upon addition of impurity (Cu) and the material may potentially be used in photonic, power electronics, solar cells, optoelectronics, UV photodetectors and LEDs.
关键词： Gallium Nitride,DFT calculation,Cu doping,Optical Properties,Density of states
更新于2025-09-23 15:19:57
-
Realizing Synergistic Effect of Electronic Modulation and Nanostructure Engineering over Graphitic Carbon Nitride for Highly Efficient Visible-Light H2 Production Coupled with Benzyl Alcohol Oxidation
摘要： Photocatalytic H2 production based on g-C3N4 faces enormous challenging issues including limited visible-light absorption, poor separation and transfer abilities of photo-generated electron-hole pairs. Herein, we realize the synergistic effect of nanostructure engineering and electronic modulation with a supramolecular assembly mediated synthesis of heteroatom doped g-C3N4 hierarchical mesoporous spheres. The favorable doping site and possible effect on electronic structure are disclosed by DFT calculation with supporting experimental analysis. Impressively, S-doped g-C3N4 delivers a 13.2 times higher H2 production rate than bulk g-C3N4 under visible-light. More importantly, as the dual functional photocatalyst for H2 production and selective oxidation of benzyl alcohol, it can exhibit outstanding activity with a H2/benzaldehyde production rate of 3.76/3.87 μmol h-1, respectively. This work not only provide a new rationale for photocatalytic performance enhancement, but also shed new light on the highly efficient utilization of solar energy by coupling H2 generation with value added chemical production.
关键词： graphitic carbon nitride,hierarchical mesoporous spheres,DFT calculation,benzyl alcohol oxidation,photocatalytic hydrogen production
更新于2025-09-23 15:19:57
-
Anion intercalated layered-double-hydroxide structure for efficient photocatalytic NO remove
摘要： Due to the easily controllable interlayer anions, metal cation composition proportion and thickness, which is beneficial to modify surface chemical state and tune bandgap, layered double hydroxides (LDHs) have great promising potential for photocatalytic applications. In this study, we have successfully synthesized the ZnAl–LDH intercalated the single anion between ZnAl cationic interlayer without anionic impurities by using a facile calcining and reconstructing routes. The electron structure and surface chemical state of the prepared products have been investigated by combining the DFT calculation and experimental characterization methods. UV–vis DRS was used to certify the light absorption of the prepared products, and we performed the DFT calculation to demonstrate the density of state and activation of reactant. These results suggested that the ZnAl–LDH–CO3 possessed the more proper band structure and superior ability to activate NO and O2 for accelerating the photocatalytic NO oxidation activity. Moreover, the In situ DRIFTS with dynamically monitoring intermediates and products over the ZnAl–LDH–CO3 was adopted to declare the photocatalytic NO oxidized process during the photocatalytic reaction process. This work illustrated the influence of different interlayer anions to the electron structure and surface chemical state of ZnAl–LDH structure through the experimental verification combined DFT calculation and the photocatalytic NO oxidized process via In situ DRIFTS analyzing, which would provide a novel way to design and fabricate the efficient photocatalysis, and understand the reaction process.
关键词： In situ DRIFTS,ZnAl–LDH,DFT calculation,Reaction process and mechanism,Photocatalytic NO oxidation
更新于2025-09-23 15:19:57
-
Hydrogen bonding promoted simple and clean photo-induced reduction of C–X bond with isopropanol
摘要： We herein report a simple and clean photo-induced metal-free reduction of C–X bond under an atmosphere of air at room temperature. Isopropanol is used as both the reducing reagent and solvent. Various functional groups (acids, esters, alcohols, anilines, phenols, indoles, pyridines, cyano and trifluoromethyl groups) and other heterocyclic compounds are tolerated. Different organic halides (including C–I, C–Br and C–Cl bonds) can be dehalogenated with moderate to excellent yields. Polyhalides are also reduced chemoselectively and efficiently. DFT calculation suggests a six-membered ring transition state via C–X···H–O hydrogen bonding to decrease the activation energy.
关键词： metal-free,isopropanol,DFT calculation,hydrogen bonding,photo-induced reduction,C–X bond
更新于2025-09-19 17:15:36
-
Two-Dimensional Hydroxyl-Functionalized and Carbon-Deficient Scandium Carbide, ScC <sub/><i>x</i> </sub> OH, a Direct Bandgap Semiconductor
摘要： Two-dimensional (2D) materials have attracted intensive attention in nanoscience and nanotechnology due to their outstanding properties. Among these materials, the emerging family of 2D transition metal carbides, carbonitrides, and nitrides (referred to as MXenes) stands out because of the vast available chemical space for tuning materials chemistry and surface termination, offering opportunities for property tailoring. Specifically, semiconducting properties are needed to enable utilization in optoelectronics, but direct bandgaps are experimentally challenging to achieve in these 2D carbides. Here, we demonstrate the fabrication of 2D hydroxyl-functionalized and carbon-deficient scandium carbide, namely ScCxOH, by selective etching of a layered parent ScAl3C3 compound. The 2D configuration is determined as a direct bandgap semiconductor, with an experimentally measured bandgap approximated to 2.5 eV. Furthermore, this ScCxOH based device exhibits excellent photoresponse in the ultraviolet-visible light region (responsivity of 0.125 A/W@360 nm/10 V, and quantum efficiency of 43%). Thus, this 2D ScCxOH direct-bandgap semiconductor may find applications in visible-light detectors, photocatalytic chemistry, and optoelectronic devices.
关键词： DFT calculation,photodetector,electronic properties,two-dimensional material,selective etching,MXene
更新于2025-09-19 17:15:36
-
Dimethylaniline functionalised pyrene fluorophores; dual colour pH switching in solution and self-assembled monolayers
摘要： A pyrene charge transfer fluorophore with three ionizable N,N-dimethylaniline moieties was explored as an interfacial pH switch. The parent carboxylate compound and the thiolated derivative were shown by spectroscopy combined with DFT calculation to be successively and reversibly protonated. Protonation leads to progressive decrease of intensity of the 550 nm centered N,N-dimethylaniline to pyrene charge transfer emission which on protonation of the third site, leads to extinction of this transition and evolution of an intense blue (450 nm) pyrene-centered emission. Concomitant loss of the charge transfer absorbance was observed and the changes are reversed on neutralization of pH. A self-assembled monolayer of the thiolated derivative was prepared on gold and found from voltammetry of ferricyanide/ferrocyanide probe to form close packed monolayers. The probe voltammetry, label-free electrochemical impedance spectroscopy of the film was monitored as a function of pH and progressive, but reversible protonation steps were reflected in decreasing film resistance. The Stokes shift of the probe prevents self-quenching so a broad, charge transfer fluorescence centered around 540 nm was recorded for the self-assembled monolayer where as per solution, progressive and reversible reduction in intensity was observed. The facile assembly, impedance and optical switching make these materials potentially interesting as on–off or two colour on–off–on fluorescence switches with potential applications in logic gates or in responsive surface applications.
关键词： DFT calculation,self-assembled monolayer,fluorescence,charge transfer,pH switch,pyrene
更新于2025-09-12 10:27:22
-
Potassium-Presenting Zinc Oxide Surfaces Induce Vertical Phase Separation in Fullerene-Free Organic Photovoltaics
摘要： Bulk heterojunction (BHJ) structure based organic photovoltaics (OPVs) have recently showed great potential for achieving high power conversion efficiencies (PCEs). An ideal BHJ structure would feature a large donor/acceptor interfacial area for efficient exciton dissociation and gradient distributions with high donor and acceptor concentrations near the anode and cathode, respectively, for efficient charge extraction. However, the random mixing of donor and acceptor in BHJ often suffers the severe charge recombination in the interface, resulting in poor charge extraction. Herein, we propose a new approach—treating the surface of the zinc oxide (ZnO) as electron transport layer with potassium hydroxide—to induce vertical phase separation of an active layer incorporating the non-fullerene acceptor IT-4F. Density functional theory calculations suggested that the binding energy difference between IT-4F and the PBDB-T-2Cl, to the potassium(K)-presenting ZnO interface is twice stronger than that for IT-4F and PBDB-T-2Cl to the untreated ZnO surface, such that it would induce more IT-4F moving toward the K-presenting ZnO interface than the untreated ZnO interface thermodynamically. Benefiting from efficient charge extraction, the best PCEs increased to 12.8% from 11.8% for PBDB-T-2Cl:IT-4F based devices, to 12.6% from 11.6% for PBDB-T-2Cl:Y1-4F based devices, to 13.5% from 12.2% for PBDB-T-2Cl:Y6 based devices, and to 15.7% from 15.1% for PM6:Y6 based devices.
关键词： DFT calculation,organic photovoltaics,potassium,vertical phase separation,non-fullerene acceptors
更新于2025-09-12 10:27:22
-
Time-Resolved Spectroscopic and Density Functional Theory Investigation of the Photogeneration of a Bifunctional Quinone Methide in Neutral and Basic Aqueous Solutions
摘要： Binol quinone methides (BQMs) can be generated from 1,1′-(2,2′-dihydroxy-1,1′-binaphthyl-6,6′-diyl)bis(N,N,N-trimethylmethanamiuium) bromide (BQMP-b) in a 1:1 MeCN:H2O mixed solution via a ground state intramolecular proton transfer (GSIPT), as mentioned in our previously reported studies. Here, the photoreaction of BQMP-b in neutral and basic aqueous solution (pH = 7, 10, 12) was investigated to explore the possible mechanisms and the key intermediates produced in the process of the photoreaction and to examine whether they are different from those in a neutral mild-mixed MeCN:H2O solution. The studies were conducted using femtosecond transient absorption (fs-TA), nanosecond transient absorption (ns-TA), and nanosecond time-resolved resonance Raman spectroscopy (ns-TR3) in conjunction with results from density functional theory (DFT) computations. The results showed that BQMP-b was deprotonated initially and produced BQMs species more effectively through an E1bc elimination reaction in a strong basic aqueous condition (pH = 12), which differed from the reaction pathway that took place in the solution with pH = 7 or 10. A related single naphthol ring molecule 1-(6-hydroxynaphthalen-2-yl)-N,N,N-trimethylmethanaminium bromide (QMP-b) that did not contain a second naphthol ring was also investigated. The related reaction mechanisms are elucidated in this work, and it is briefly discussed how the mechanisms vary as a function of aqueous solution pH conditions.
关键词： E1bc elimination reaction,time-resolved resonance Raman,DFT calculation,bifunctional quinone methides
更新于2025-09-09 09:28:46
-
A 1,8 Naphthalimide anchor Rhodamine B Based FRET Probe for Ratiometric Detection of Cr3+ion in Living Cells
摘要： A 2-(1,3-dioxo-1H-benzo[de]isoquinolin-2(3H)-yl)acetaldehydeanchored rhodamine B based probe, RDNAP detects Cr3+ ion by fluorescence resonance energy transfer (FRET) process in aqueous buffered acetonitrile media (7:3, v/v). Conversely, conjugation of 2-(1,3-dioxo-6-(piperidin-1-yl)-1H-benzo[de]isoquinolin-2(3H)-yl)acetaldehyde with rhodamine B provides another probe, RDNAP-PY that undergoes Cr3+assisted ratiometric fluorescence and colorimetric change in the same media. RDNAP-PY provides higher FRET efficiency and detects as low as 1.81×10?6 M Cr3+with an association constant, 15.9 × 104 M-1. Other common ions do not interfere. RDNAP-PY efficiently images intracellular Cr3+ in live Hep3B, MCF-7, HeLa, SiHa and HEK 293T cells under fluorescence microscope in a ratiometric and time dependent manner. 1H NMR titration and DFT studies strongly support experimental findings.
关键词： 1,8 Naphthalimide,Live cell imaging,Ratiometric probe,fluorescence resonance energy transfer,DFT calculation
更新于2025-09-09 09:28:46